I would like to find details of the algorithm used to work this out. I one of my first long journeys I could not understand how my P300e was deciding how to use battery vs petrol. At one stage the battery seem to drop from just under 50% to zero very quickly. Another thing that only happened once on my 150 mile journey was that the petrol engine was directly charging the battery, but only for a few minutes. I would like to understand the logic. The electronic handbook is no help, it doesn't mention engine charging at all as far as I can see.